The Science of Smallpox

by Vijaya Khisty Bodach

The smallpox virus is a bomb. Variola major is large, spiky, and brick-shaped. Like all viruses, it needs to grow inside a host cell, which, unfortunately, humans provide. Other animals also have pox viruses, including cowpox, monkeypox, and even insectpox.

Smallpox is very contagious, and that's why it is considered a “Category A” bioterrorist threat by the Centers for Disease Control and Prevention (CDC) in Atlanta, GA. You could get it by just standing next to somebody who has it. It's that dangerous! But don't worry—smallpox has been eradicated from the human population. However, it has not been wiped off the Earth. The virus has been stored in deep-freezers in America and Russia and probably other countries, too. It could be a potent biological weapon.

The Biology of Smallpox

Smallpox is spread when a person breathes it in…and out. The virus gets inside the cells lining the throat and hijacks the cellular machinery to make millions more smallpox viruses. The cells explode, releasing smallpox “bombs.” Those virus particles go on to infect other cells in the body. After a week, the person gets a high fever. Then comes the rash—red, itchy spots that grow into blisters. After another week, the blisters dry and crack and turn into scabs. A month later, the scabs fall off, leaving deep pits in the skin. The good part is that the person will never suffer from smallpox again—if he or she survives.

The bad part is that the infected person can die. How? From all those exploding cells. Remember that your body is an organized collection of different types of cells. If one cell is damaged, that's not a problem. But when millions of cells are damaged and entire organs are destroyed, you fall apart from the inside out. And that's exactly what happens in the most severe cases of smallpox. It's a gruesome way to die.

Unfortunately, the smallpox virus doesn't die with the death of its host. Blood carries the virus to its next victim. The scabs of victims are full of virus. The victim's clothes and beds are infectious for days or even months.

The Fight Against Smallpox

People noticed that survivors of smallpox never got it again. So some deliberately tried catching a milder version of smallpox called Variola minor. This process was called variolation and protects the person from getting the more severe form of the disease. Although it saved many lives, this practice also kept the virus in the population.

Edward Jenner was an English country doctor in the late 1700s who knew his patients well. He was a kind and caring man who took the trouble to listen to his patients. A milkmaid once told Jenner that she did not fear smallpox because she already had had cowpox. This idea stayed with Jenner for a long time. He talked about it with several doctors, but they didn't want to believe some old wives' tale about cows and milkmaids.

A decade later, when there was a simultaneous outbreak of cowpox and smallpox, Jenner decided to test the hypothesis that an infection of cowpox could prevent smallpox. Sarah Nelmes, a milkmaid, came down with cowpox. Jenner collected some of the pus from the blister and “vaccinated” James Phipps, a boy of eight. He used the term “vaccination” to distinguish it from “variolation,” because “vacca” is “cow” in Latin. A couple of months later, he tried inoculating the boy with the mild form of smallpox. The boy resisted it—he did not get smallpox!

Jenner published his findings from numerous cases, but people didn't believe him. They were afraid of vaccination. They thought that a blister from a cow could turn them into a cow. Others saw it as tampering with nature. Ultimately, people saw that vaccination was safe, and in the early 1800s the practice spread all over Europe and eventually the world.

The Eradication of Smallpox

In 1967, the World Health Organization (WHO) took it upon itself to rid the world of smallpox. Instead of trying to vaccinate everybody, they used a method of vaccination combined with isolation. That is, when they found someone with smallpox, they vaccinated everybody who had or could come in contact with that person. In addition, they isolated the sick person until that person was no longer infectious. This method worked.

We won the war on smallpox. In 1980, WHO declared “the world and its people” free from smallpox. The virus had one fatal flaw: It could use only one host—humans. Once the chain of infection was broken, there was nowhere that the virus could hide.

The Demon in the Freezer

Smallpox remains in freezers—for research purposes. And, for deadly purposes. Throughout history, smallpox was used as a weapon. Today, most of us have no experience with pox viruses. We are now like the Aztec or Inca long ago. If someone were to unleash one upon us, most of us would die.

In light of the terrorist attacks on September 11, 2001, the U.S. government is preparing for a possible smallpox attack. Large quantities of vaccines are being made. Our military troops and frontline medical teams that would respond in an attack have been vaccinated. Doctors are learning to recognize smallpox. If there is an outbreak, you and your family will have to make tough decisions. Will you get vaccinated? Will you be willing to be isolated if you catch the disease? Will you give up your civil liberties for the greater good of this world?

Let us hope that those decisions will not be necessary. Let us hope that no one will undo one of the great achievements of science and humanity.

A Shot in the Arm—How Vaccines Work

by Vijaya Khisty Bodach

Ouch! Shots hurt. But they prevent you from getting sick. How? by teaching your body how to fight germs. Some vaccines contain a few germs of a specific disease that have either been killed or weakened, so the shots can't give you the disease. Many modern vaccines contain only highly purified parts of the germs.

Trillions of white blood cells called “B cells” patrol your body. Each one is programmed to recognize a bit of something that is not part of you. When a germ gets inside your body and meets its match, that B cell becomes active. It replicates itself, and thousands of identical B cells secrete large molecules called antibodies. The antibodies bind to get the germ and destroy it.

Germs multiply very quickly. One germ can turn into a million in a few hours. If you're unlucky or weak, you will feel sick and succumb to the infection. Meanwhile, your B cells are working hard. They usually take about one to two weeks to catch up with the growing number of germs. At the height of the battle, each cloned B cell can make thousands of antibodies in a second. That's when you start feeling better.

After the germs are vanquished, you think your body goes back to the way it was. And it does, except that now it knows how to fight those specific disease germs because some of those cloned B cells are memory B cells. Sometimes they can live for your entire life. They make you safe from a second infection. That is the basis for vaccination. Vaccines contain dead or weakened germs that let your body make memory B cells without making you sick at all.

Later, if you come across that same germ, the memory B cell is armed and ready to fight. It immediately starts replicating itself and making antibodies. In less than one week, the germs are destroyed and you probably won't even feel sick.

When Edward Jenner used cowpox to protect people from smallpox, he had no idea about viruses or B cells or antibodies. But he was observant and he followed his instincts. Now we know that cowpox and smallpox are similar enough that the antibodies made against cowpox also kill the smallpox virus for a time. However, to get lifelong immunity, you have to suffer a case of smallpox.

A hundred years after Jenner, Louis Pasteur systematically laid the foundations for vaccination—using a germ against itself.

Vaccines—they really are magic bullets.

Vocabulary

biological weapon: A biological agent, such as a virus, used in an attack.

Activity

The article mentions that, in the future, people may need to make choices about whether or not they get certain vaccines. Another debate focuses on whether or not people would be willing to be isolated if they caught contagious diseases that put large portions of the population at risk. Choose one of these issues, and write a paragraph explaining why some people support the issue and why some people oppose the issue.[anno: Answers will vary but could include reasons for opposing certain vaccinations, such as the fear that new vaccinations have not been thoroughly tested for long-term effects. In support of the vaccinations, answers might include that by vaccinating people against diseases that could potentially be used as biological weapons, the country's citizens are safer from terrorist attacks. In opposition to isolation, answers might include that someone's personal freedoms are being violated. In support of isolation, answers might include that isolating infected individuals is the only way to protect the general public.]